Eating Too Much Salt May Lead to Multiple Sclerosis, Other Autoimmune Disorders

Overall, people who ate three to six grams of sodium, which is equivalent to eight to 15 grams of salt, had the lowest risk of heart disease or death from any cause. (Photo : Flickr/crayonbeam)

By now, we all know that we should stay away from eating too much salt. Excess salt intake has been linked to heart problems, including cardiovascular disease, high blood pressure and high cholesterol. A recent study suggests that too much salt may have other unintended consequences: autoimmune disorders like multiple sclerosis and psoriasis. The study may lead to new information about what leads to autoimmune disorders, the origins of which still remain hazy.

In much of the developed world, there has been a sharp increase in the number of autoimmune disorders over the past few decades. Because that increase cannot be attributed to genetic factors, researchers have attempted to trace the environmental origins, like lifestyle changes and dietary habits. In much of the Western world, these past few decades have also correlated with a rise in fast food, which tends to have greater amounts of salt than home-cooked meals. A study conducted by researchers from Yale School of Medicine, Vanderbilt University and the University of Erlangen-Nuremberg in Germany is the first to explore the link between salt and autoimmune disorders.

The study examined a type of T-cell called Th17, which produces cytokine interleukin 17. In healthy bodies, Th17 cells are deployed to fight infection, but researchers believe that these cells are pivotal to the development of autoimmune disorders.

The researchers found that an excess of sodium chloride - salt - led the number of Th17 to change. "In the presence of elevated salt concentrations this increase can be ten times higher than under usual conditions," study authors Markus Kleinewietfeld and Dominik Müller said in a statement.

The researchers also performed an experiment with mice. When mice's intake of salt was increased, many suffered from an extreme form of autoimmune encephalomyelitis, a mice model for the human condition multiple sclerosis. The condition in humans is caused by the body's immune system attacking the myelin sheath of neurons, which lead to a number of neurological problems and permanent disability.

"It would be interesting to find out if patients with psoriasis can alleviate their symptoms by reducing their salt intake," the researchers stated. "However, the development of autoimmune diseases is a very complex process which depends on many genetic and environmental factors. Therefore, only further studies under less extreme conditions can show the extent to which increased salt intake actually contributes to the development of autoimmune diseases."